Here’s a debate I have with myself. In the old days of cuttings libraries and house telephones, when social media meant the Society Correspondent of the Daily Telegraph and when there were fewer TV channels than fingers on my hand, many of the arguments and people that seem to convulse political debate in Britain today were simply not known about. You’d only find out about the fringe if they became violent on a demonstration that happened to be televised.

Today, the words of some nudnik, uttered or amplified by Twitter and Facebook and then taken up by the conventional press (that’s me, folks) assume an importance denied to them in pre-web days. So my internal question always is, does this latest outrage or storm actually amount to no more than knowing about trivial things you didn’t know about before? Or have the changes in what everyone reads or sees actually conferred an importance on things that previously we wouldn’t have noticed?

And so to Jon Lansman, the Jewish head of the group Momentum, which has, with its occasional allies in the trade unions, largely taken over the machinery and leadership of the Labour Party. What Mr Lansman thinks and advocates is of some account.

The most recent storm concerns the attacks on him in social media from people who may or may not be members of the Labour Party, almost always posted under noms de plume, for being variously a tool of Israel and an employee of the Labour branch of the Elders of Zion. The Z word has been liberally employed.

Mr Lansman’s crime has been to announce his intention to stand as general secretary of the Labour Party, against a union apparatchik called Jennie Formby who, as chance would have it, is big on the Middle East. Which, in the way of these things, actually only means Palestine; her last tweet on Palestinian children was last week. Syria not so much; her last tweet on Ghouta was never.

So Lansman is being cast, essentially, as the man the Rothschilds have put in to thwart the woman who is the champion of the Palestinian cause and the hammer of the Zionists.

As these things go, Lansman is a moderate on Israel and antisemitism. He loathes Bibi and the Israeli right, which seems sensible to me. He’s a two-state man and though not much of a Zionist himself, deplores the use of the word “Zionist” as a term of abuse. He points out that most Jews are Zionists. He agrees there is a problem with antisemitism within the Labour Party. After Ken Livingstone’s Hitler moment he called upon the former mayor to leave politics.

But Lansman, otherwise so very up-to-date in his Corbynism, is not where the true activists are on Israel and Zionism. Ms Formby, with her reflexive and narrow anti-Zionism is much more representative of the mood. When in 2016 Corbyn regretted having called Hamas and Hezbollah his “friends”, many of these activists will have rationalised that he was simply forced for the moment into being politic.

For students of anti-Zionism and borderline antisemitism (and sometimes worse) there has been much to ponder in the past couple of years. Even someone as extreme as Tony Greenstein — expelled from Labour recently — has been called a Jewish tribalist by that Judaeophobic jazz musician Gilad Atzmon whom Greenstein in return calls an antisemite and a Holocaust denier. Atzmon for his part has been lionised by George Galloway who claimed to have read chapters of one of Atzmon’s appalling anti-Jewish books to his wife in bed. The other week, Greenstein was on Galloway’s Russian government funded TV show, Sputnik and no one mentioned Atzmon. Pals for now in battling the witch-hunt.

Then there’s Jackie Walker, Ken Livingstone, Ken Loach and the “Zionists helped in the Holocaust and Jews funded the slave trade” brigades. All there roiling on fringes that for the most part are better at fighting each other than fighting anyone else. Do they matter?

Fringe though they may be they can make life uncomfortable in certain places, for example for Jewish students in some colleges. But even more importantly this stuff is now leaking into the mainstream. The Rothschilds have probably have never heard of Jon Lansman; the “anti-Zionists” have certainly heard of Jennie Formby. Lansman is not, of course, any kind of Zionist candidate. Formby, however, is very much seen by the activists as their woman. It matters to them if she becomes Labour’s general secretary and it probably ought to matter to you.

David Aaronovitch is a columnist for The Times